The brains of college football players are subtly different from the brains of other students, especially if the players have experienced a concussion in the past, according to an important new brain-scan study.

While restrained in its conclusions, it adds to concerns that sports-related hits to the head could have lingering effects on the brain, even among the young and healthy.

A subtype of Alzheimer's disease has been identified by neuroscientists that they say is neither well recognized nor treated appropriately. The variant, called hippocampal sparing AD, made up 11 percent of the 1,821 AD-confirmed brains examined by researchers, suggesting this subtype is relatively widespread in the general population.

Autopsies have revealed that some individuals develop the cellular changes indicative of Alzheimer's disease without ever showing clinical symptoms in their lifetime. Additionally, memory researchers have discovered a potential genetic variant in these asymptomatic individuals that may make brains more resilient against Alzheimer's.

One of the first long-term studies into Alzheimer's disease checked over 3,330 '18 to 30-year-olds' every two to five years and found that young people who keep their hearts healthy may be less likely to be diagnosed with Alzheimer's in later life.

The narrowing of the carotid artery may be linked to problems in learning, memory, thinking, and decision-making, according to research presented at last week's American Academy of Neurology annual meeting in Philadelphia.